Display device and connector therefor



J1me 1970 T. v. RYCHLEWSKI 3,517, 51

DISPLAY DEVICE AND CONNECTOR THEREFOR Original Filed May 27, 1964 2Sheets-Sheet 1 IINVENTOR. flmppzus V, FYC/ILEWSK/ Z4 AITORNEY June 30,1970 T. v. RYCHLEWSKI DISPLAY DEVICE AND CONNECTOR THEREFOR 2Sheets-Sheet 2 Original Filed May 27, 1964 INVENTOR.

77141519503 M RYC/ILZWS/(l United States Patent Oflice 3,517,451Patented June 30, 1970 ABSTRACT OF THE DISCLOSURE A numeric readoutdevice and a process of making the same which utilizes the edgeillumination of excited electroluminescent material. The device isfabricated by applying the electrodes and EL material to the peripheryof a substrate rather than to the planar surface thereof. This procedureallows the use of thin line figures while maintaining large electricalcontact areas for ease of electrical connection. The device producedthereby has a polygonal central core with separate outermost connectorsand is mounted for use on an insulating connector board having connectorpins formed therein to hold the display in position and provideelectrical connection thereto.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a divisionalapplication of Ser. No. 370,655, filed May 27, 1964, now U.S. Pat. No.3,370,976, granted Feb. 27, 1968, which is assigned to the assignee ofthe present invention and it contains matter disclosed but not claimedin Ser. No. 695,758, now US. Pat. No. 3,484,975, granted Dec. 23, 1969,filed Jan. 4, 1968, concurrently herewith, which application is also adivision of Ser. No. 370,655.

BACKGROUND OF THE INVENTION This invention generally releates to displaydevices and to a method of making the same. More particularly, itrelates to illuminable symbolic and numeric readout displays and amethod of making them.

The tredemendous increase in the number of electronic computing andtesting devices has created a need for visible display unit which may beutilized in visually portraying the information derived therefrom. Therehave been many types of these units, all of which have been more or lesssuccessful. These include mechanical counters, gas glow tubes,projection devices, and segmented electroluminescent displays. Thisinvention pertains to the latter type of device.

The usual type of segmented electroluminescent display is comprised ofan electrically insulating planar substrate having a particular,electrically conductive, segmented pattern affixed thereto. Overlyingthis pattern is a layer of an electroluminescent phosphor which may ormay not be dispersed in a dielectric medium such as plastic or glassfrit. A common transparent, electrically conductive electrode overliesthe electroluminescent layer. When a potential is applied between thecommon transparent electrode and any one or several of the conductivesegments, the electroluminescent phosphor therebetween will be excitedto luminescence. These devices are quite superior to many of the typesin common usage today in that they are not subject to catastrophicfailure. They have, however, several disadvantages. Among these are theproblems of constructing small displays and the difficulty of providingelectrical connection to the various segments.

OBI ECT S AND SUMMARY OF THE INVENTION It is, therefore, an object ofthis invention to provide a small symbolic readout display havingimproved manufacturability.

It is another object of this invention to provide an improvedelectroluminescent readout device.

Another object of this invention is to provide improved means for makingelectrical connections to readout devices.

Still another object of the invention is to provide a readout devicehaving an improved structure adapted to the economic fabricationthereof.

The above objects are carried out in one aspect of the invention by theprovision of a method of making illuminable symbolic readout displaywhich comprises coating the peripheral surface area of a rod having agiven geometrical configuration, and at least the peripheral surface ofwhich is electrically conducting, with an electroluminescent phosphor.Next, an electrically conductive coating is applied over the phosphor,and the discrete areas of the conductive coating are removed whereby aplurality of individually illuminable electroluminescent segments isprovided.

It will be seen that, by the use of this method, relatively small andrugged electroluminescent symbolic displays may be fabricated since thesize will be controlled by the dimensions of the rod. By making the rodlonger than the phosphor layer, electrical connection may be easilyaccomplished to the inner electrode. By forming several symbolicdisplays and assembling them together, numeric segmented displays may beprovided.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 through 5 illustrate thesequence of operations for fabricating one type of symbolic displaydevice;

FIGS. 6 through 9 illustrate the sequence of operations for fabricatinganother type of symbolic display device; and

FIG. 10 is an exploded perspective view illustrating a type of numericreadout display which may be assembled from the two symbolic displaydevices.

DESCRIPTION OF THE PREFERRED EMBODIMENT For a better understanding ofthe present invention, together with other and further objects,advantages, and capabilities thereof, reference is made to the followingdisclosure and appended claim in connection with the above-describeddrawings.

Referring now to the drawings with greater particularity, in FIG. 1there is shown a rod 12 of some suitable opaque material such as glassor ceramic or electrically conductive metal. If rod 12 is metal, theelectroluminescent phosphor may be applied directly thereto; however, ifthe rod i glass or ceramic or some other electrically insulatingmaterial, then an electrically conductvie coating such as 14 in FIG. 2would have to be applied thereto .to provide an inner electrode. Coating14 may be any suitable and easily applied material such as aluminum orgold.

Phosphor layer 16 is then applied to coating 14 by any conventionalmeans, as by spraying, and may consist of all phosphor or phosphorparticles dispersed in a dielectric medium such as glass frit orplastic. Layer 16 does not extend the entire length of rod 12 so thatelectrical connection can be made to coating 14.

Conductive coating 18 may be applied over layer 16 by suitable means toprovide the construction shown in FIG. 4; and then selected, discreteareas of coating 18 are removed to form a plurality of individual outerelectrodes 20, 22, 24, 26 which provide individually illuminableelectroluminescent segments in a first symbolic display device 28. Whilerod 12 is shown in this instance as having a substantiallyparallelogrammatic configuration, it is to be understood that otherpolygonal configurations may be used for other purposes with equalsuccess. For example, if rod 12 had a decagonal configuration, atensegment decade counter could be produced.

Symbolic display devices constructed according to the method of thisinvention provide a distinct advance in the art. Small, rugged units ofvirtually any configuration can be constructed, and electricalconnection to the various electrodes can be easily accomplished.

To construct a numeric readout display; that is, a display whichportrays the conventional physical characteristics of numbers, thefollowing approach has been tried:

An electrically insulating rod, 30, similar in size and configuration torod 12, has first and second electrically conductive coatings, 32, 34respectively, applied thereto as is shown in FIG. 6. Coating 32 extendsthe full length of rod 30 and encompasses substantially three surfacesthereof. Coating 34 is adhered to the previously uncoated surface and isinsulated from coating 32 and also extends the full length of rod 30.

Phosphor layer 36 is applied by suitable means to overlie coating 32,and a third electrically conductive coating 38 is applied thereover.Again, layer 36 and coating 38 preferably do not extend the full lengthof rod 30. Selected, discrete areas of coating 38 are then removed, asby grinding to form a plurality of electrodes 40, 42, 44 Which provideindividually illuminable electroluminescent segments in a secondsymbolic display device 46.

While it has been suggested to apply coating 18 and coating 38 in a moreor less enveloping manner and then remove selected, discrete areasthereof to form electrodes, it will be obvious to those skilled in theart that the electrodes could be individually applied.

Numeric readout display 48 is formed by combining a first symbolicdipslay device 28 and a second symbolic display device 46 in the stackedmanner shown in FIG. 10. Preferably they may be cemented together by aconductive epoxy. This unit is then afiixed in connector board 50 by anysuitable means, such as by cementing. Board 50 may be any electricallyinsulating material having good strength characteristics; and it isprovided with connector pins 52, 54, 56, 58, 60, 62, 64, 66 whichprovide .electrical contact with electrodes 40, 32, 34, 42, 14, 22, 24,

26, and 44 respectively. The connector pins project through board 50 sothat the entire unit may be connected to suitable electrical potentials.

This device is small and rugged and is relatively economical tomanufacture, and it greatly simplifies the job of making electricalconnection to the various segments.

While there have been shown and described what are at present consideredthe preferred embodiments of the invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing from the invention as defined by the appendedclaims.

I claim:

1. In combination, a device for illuminatingly displaying selectivelyvariable, intelligence conveying symbols and a connector board therefor,said device comprising: at least one elemental unit having a polygonalcentral core having a plurality of substantially flat sides and a givenlength and at least the surface of which is electrically conductive toprovide an inner electrode; an electroluminescent phosphor having alength less than said given length substantially surrounding said innerelectrode; and a plurality of individual outer electrodes disposed onsaid phosphor, one outer electrode for each of said sides; saidconnector board comprising an electrically insulating substrate having aplurality of electrically conductive connector pins formed therein, atleast one of said pins being formed to contact said inner electrodes andat least some of the remaining pins being formed to contact said outerelectrodes.

2. The invention of claim 1 wherein said device is comprised of two ofsaid elemental units stacked one upon the other.

3. Th invention of claim 2v wherein said devices are releasably mountedby said pins.

References Cited UNITED STATES PATENTS 1,894,380 1/1933 Long l302,878,418 3/1959 Garfinkel et a1 40l30 X 2,942,157 6/1960 Davis 3l71l93,133,221 5/1964 Knochel et al 313-408 WILLIAM H. GRIEB, PrimaryExaminer

